Effect of addition different levels of soybean milk to tris diluent on the freez ability and fertility of Holstein bulls semen

Abstract EN

The aim of the present study was to use different levels of soybeanmilk as a cryoprotectant in Tris-extenders and to investigate its effect on quality and fertility of frozen Holstein bulls semen.

Semen was collected once weekly from five Holstein mature bulls for 12 weeks.

After evaluation of semen quality, the pooled fresh semen was divided into five equal fractions, one fraction was diluted with Tris-egg yolk extender (control) and the other four tests media, whole egg yolk was replaced by different concentrations of 4; 7; 10 and 13% soybeanmilk extracted.

Percentages of spe m motility, live spermatozoa, acrosome integrity and plasma membrane integrity were assessed, post-dilution, pre-freezing and post-thaw processes.

The results revealed that there were no differences among the percentages of sperm motility, live spermatozoa, acrosome integrity and plasma membrane integrity in different extenders in post-diluted semen.

In Post equilibration and post thawing processes, the corresponding values were significantly (P < 0.05) higher in extenders containing 7 and 10% of soybean milk compared with control, while the lowest values were recorded at a level of 13% of soybean milk extender.

Higher fertility rate was recorded in cows inseminated with frozen semen diluted with 7 or 10% soybean milk (68.3% and 66.2%, respectively) compared with 20% egg yolk (61.8%).

In conclusion, 7% soybean milk extender improves the freezability and fertility of Holstein bull spermatozoa and can be used as an alternate to egg yolk in cryopreservation of bull semen.